Double air chamber brake cylinder



May 21, 1963 D. HoPPENsTAND DOUBLE AIE CHAMBER BRAKE CYLINDER 3 Sheets-Sheet 1 Filed Dec. 5, 1960 2 4 a.; 2 m. I

David 'Hoppensfand his ATTORNEY May 21, 1963 D. HOPPENSTAND 3,090,359

DOUBLE AIR CHAMBER BRAKE CYLINDER Filed Deo. 5, 1960 3 Sheets-Sheet 2 26 l /fll\ I6' 19 28 23 d 1213 W /17 la 31 27 29 l l5 l 32 so Fig.3

l 5% 2o 11,1!!! Y WA lr/f INVENTOR. David Hoppensfand his ATTORNEY May 21, 1963 D. HoPPENsTAND 3,090,359

DOUBLE AIR CHAMBER BRAKE CYLINDER Filed Deo. 5, 1960 3 Sheets-Sheet 3 INVENTOR. David Hoppensand BY 5%f his ATTORNEY 3,090,359 DUBLE Am CHAMBER BRAKE CYLINDER David Hoppenstand, Miami Beach, Fla., assignor to Transport Industries, Inc., Albion, Pa., a corporation of Penu- Sylvania Filed Dee. 5, i960, Ser. No. 73,699 8 Claims. (Cl. 121-38) This invention rela-tes to motor vehicle braking mechanisms, and is more particularly concer-ned with a iiuid operated brake motor or cyl-inder having improved safety features.

It is `well known to provide motor trucks, buses and the like with power brakes. Those brakes are usually iluid operated and the most commonly used operating uid is air. My invention will be described hereinafter as an air operated brake motor or cylinder but it is adaptable for use with other operating uids.

U.S. 'Patent 2,936,785 issued to Robert M. Hastings on May 17, 1960, discloses a double diaphragm brake cylinder which provides a liuid 'operated service brake together with a iluid operated emergency or hand brake having additional braking effect. The :additional braking effect in that patent is obtained by imparting additional travel Ito the brake operating rod. It is an object of my invention to provide a brake cylinder having the advantages of the apparatus of the Hastings patent together with `the further advantage that the additional braking effect is not impaired by a leakage lor rupture of the service brake diaphragm.

It is another object of my invention to provide a double air chamber brake cylinder with positive spring operated emergency braking means effective in the vent of air failure. It is another object to provide such a brake cylinder with positive mechanical means for retracting the spring means. I-t is another object fto provide a double air `chamber brake cylinder -with emergency braking means which are both spring operated and air operated. Still other objects of my invention will become evident in the course of the following description thereof.

Embodiments of my invention presently preferred by me are illustrated in the attached figures, to which reference is now made:

FIGURE l is a section through ia double air chamber brake cylinder of my invention showng both service and hand brake chambers in the olf posi-tion.

FIGURE 2 illustrates the apparatus of FIGURE l with air admitted to the service brake chamber.

FIGURE 3 illustrates the apparatus of FIGURE 1 with air admitted to the hand brake chamber.

FIGURE 4 is a section through another embodiment of my invention including service and hand brake air chambers together with a spring brake chamber.

FIGURE 5 is a piping diagram for fthe apparatus of FIGURE 4.

FIGURES 6a and 6b show the flow pattern of the fourway valve 40 of FIGURE 5 in its two positions.

My invention as embodied in FIGURES 1, 2 and 3 hereof is con-tained within ta covering shell y1 which is generally cylindrical in shape and is closed by a dished bottom plate 2. A second dished plate 3 inverted with respect to bottom plate 2 is assembled between shell 1 and bottom plate 2 so las to form with bottom plate 2 a first closed housing or chamber separate from the remaining space within shell 1. A ilexible diaphragm 4 is positioned between plates 2 and 3 and that assembly is fastened to shell 1 with screws 5.

Within shell l is disposed -a -generally `cup-sh-aped element 6, the bottom of which is contiguous but not attached to plate 3. A dished plate 7 inverted with respect to cup 6 is assembled with it so as to form a smaller or 3,090,359 Patented May 21, 1963 secondary housing separate from that formed .by plates 2 and 3. IA ilexible diaphragm 8 is positioned between plate 7 and cup 6 and the assembly tis fastened together with screws 9.

A push plate 11 is disposed against the face of diaphragm 4 on the same side as plate 3. Plate 11 is attached to one end of push -rod 12 which extends through plate 3 and cup 6. Plate 3 is fitted with a sealing ring I3 surrounding push rod 12 so that rod 12 may move with respect to plate 3 without leakage of air therebetween. Cup 6 is iitted with a like sealing ring l14. The other end of push rod 12 is attached to push plate 15 which is positioned between cup 6 and diaphragm 8.

On the other side of diaphragm 8 from push plate 15 is positioned push plate 16, which is attached tto `one end of brake operating rod .17. The other end of rod .17 extends through plate 7 and the end of shell 1 to connect with the brake shoes, which are not shown. A compressible coil spring 18 is disposed laround brake rod 17 between 'the end of shell t1 and push plate 16. Spring 18 passes through a clearance opening 19 in plate 7.

An vair port or inlet 20 is provided in plate t2, and an air pipe 21 in the Wall of element 6 projects through a clearance opening 21a in the wall of shell 1. Opening 21a is dimensioned to permit pipe 21 to move in the direction of movement of brake rod 17. Pipe 2.1 is connected to ya source of air under pressure, not shown, through a conventional valve oper-ated by the vehicle foot brake pedal, not shown. lPort 20 is likewise connected to a source of air under pressure, not shown, through a conventional valve operated by the yvehicle hand brake lever, not shown.

The distance between plates 2 and 3 through which diaphragm 4 can be ilexed is greater than the distance between cup 6 and plate 7 through which diaphragm 8 can be flexed.

The operation of the apparatus above described will be understood by reference to FIGURES 1, 2 and 3. As I have mentioned, FIGURE 1 illustrates my apparatus as vit appears when neither the foot brake nor the hand brake is applied. When no air under pressure is admitted through either port 20' or pipe 21, diaphragm 8 is forced against push plate 15 by spring 18. Push plate 15 in turn is forced against cup-shaped element y6, and that rcup is forced against plate 3. Push plate 11 is like- Wise forced against diaphragm 4 by push rod 12, and that diaphragm is forced against end plate 2.

When ai-r under pressure is introduced throng-h pipe 211, it causes diaphragm 8i to Hex towards plate 7, moving push platte 1'6 and brake rod 117 to the right lin FIGURE 2 and compressing spring 18 between push plate 16 and the end of shell 1. FIGURE 2 shows .the position of my apparatus with full air pressure 'behind diaphragm 8. The travel `of brake rod 17 in the position there shown is suicient to apply the wheel 'brakes fully.

It is well known, however, that brakes wear, and fade when subjected to prolonged overload. My apparatus is designed to provide elfective braking even under those conditions, in a manner now to be described. 'When air under pressure is admitted to port 20, by operation of the hand brake lever previously mentioned, diaphragm 4 is ilexed toward plate 3. That movement of diaphragm 4 moves push plate 111 and push rod 12 attached thereto towards the right in FIGURE 2. yPush plate 1-5 carried by push rod l1 2 is also moved in the same direction, and if suihcient 'air is admitted through port 20; ldiaphragm 4 is eXed until push plate 15 comes up against diaphragm 8. If the full -air pressure has previously been applied to diaphragm 8, it will be flexed `against plate 7 as is shown in FIGURE 2, and push plate 15 cannot move .it further in the same direction without moving the entire secondary housing comprising cup 6 vand plate 7, and this is .viously described.

what it does. The position of my `apparatus with full air pressure behind diaphragm 4 is shown .in FIGURE 3. It Will be noted that'cup 6 has been moved away from plate 3 a distance equal to the diierence between the maximum ydisplacement of diaphragm 4 and the maximtun displacement of diaphragm 8. The extra travel thus imparted to brake 'operating rod 17 counteract-s brake wear 'and brake fading and makes possible effective braking in all circumstances.

The apparatus of my invention will be effective even though .the 'air line to pipe 2l breaks, .or the service brake diaphragm 8 ruptures. When full air pressure is admitted behind diaphragm 4 it is moved into the position shown in FIGURE 3 and push 4rod 12, through push plates 11 and 15, imparts the same movement to diaphragm =8, whether or not there is any air pressure behind it.

yFIGURE 4 -illustrates another embodiment of my invention in which the apparatus above described is modied by the addition of a spring mechanism to provide automatic emergency braking in the event of a total ail ure of air pressure. Elements that are common to the embodiments of FIGURE 4 and FIGURES 1, 2 and 3 are iden-tiiied -by the same reference charac-ters in all rigures.

In rthe embodiment of FIGURE 4 bottom plate 2 previously described is replaced by bottom cover 22 which is cylindrical in shape. The closed end of cover 212 is formed with a centrally located cylindrical indented or depressed por-tion 23 having -a at bottom or end 24. A stud 27 passes through a clearance opening in end 24, which is provided with a sealing ring 29 similar to sealing rings 13 and 14 previously described. The inner end of stud 27 is attached to a push plate 25 positioned between diaphragm 4 and end 24 of bottom cover 22. A continuation of ithe inner end of stud 27 passes through diaphragm 4 yand is attached to push plate 11 and push rod .12 pre- 'Nested compression coil springs 26- 26 positioned in the annular channel formed by the end of bottom cover 22 and its indented portion 23, between the bottom of that channel and push plate 25. A threaded 4nut 2S mat-ing with threaded end 31 of stud 2-7 is provided for a purpose to be described. =An air inlet pipe 30 is provided in plate 3. tAn air inlet pipe 3-2 is provide in cover `22.

The service brake portion of the embodiment `of my FIGURE 4 operates in the same manner as the service brake portion of Ithe embodiments of my FIGURES l, 2 and 3, and requires no further description.

The oper-ation of my apparatus shown in FIGURE 4 will be described rst with air inlet pipe 32 shut olf. Compression coil springs 26-25 urge brake rod 17, through push rod 1-2 and push plates 11 and 15, towards the right `in, FIGURE 4. In the absence of any countervailing force, therefore, springs 2.6--26 apply the brakes to a vehicle equipped with myv apparatus. When 4air under pressure is admitted through 4air inlet pipe 30 into the closed housing formed by cover 22 and plate 3, -it ilexes diaphragm 4 toward the lef-t in FIGURiE 4, and my apparatus assumes Ithe position shown in FIGURE 4. Under normal running conditions full air pressure is applied against springs 26-216 so that they are compressed. The hand brake is applied by cutting oiii air from pipe 3@ and allowing that pipe to exhaust to the atmosphere. Springs 26-26 are thus permitted to move diaphragm 4 and all other elements of my .apparatus moved thereby, in the Way previously described herein.

`Maximum safety is obtained when my apparatus is operated with both inlet pipes -30 and 32 connected to a source of air under pressure in the way shown in FIG- URE 5. -Air .reservoir 34 is connected through pipe 35, foot control valve -36 and pipe 37 to air inlet pipe 21. Air reservoir 58 is connected through pipe 39 lto a conventional vfour-way valve 4t) which is hand operated. fOne port of valve 40 is connected through pipe 41 to air inlet pipe 30, while the other port of valve 40 is connected through pipe 42 to air inlet pipe 32. The llow pattern through valve 40 in its tWompos-itions is shown by FIG- URiES 6a and 6b. In FIGURE 6a pipe 41 is connected -to pipe 39 and pipe 42 is opened to the atmosphere through exhaust port E. In FIGURE 6b pipe 42 is connected to pipe 39 and pipe 41 is opened to the atmosphere.

When the hand valve 4t) is in the position shown in FIGURE 6a, air under pressure from reservoir 38 is admitted through inlet pipe 30 between diaphragm 4 .and dished plate 3, so as to move diaphragm 4 to the left in FIGURE 4 and compress springs t25-M. At the same time air inlet pipe 32 is open to the atmosphere so that there is no air pressure between diaphragm 4 and cover 22. Under these conditions the vehicle is braked by the service brake, operated by foot control valve 36.

When emergency braking becomes necessary valve 40 is turned to the position shown in FIGURE 6b. Air under pressure from reservoir 3S is admitted through air inlet pipe 32 between diaphragm 4 and cover 22, thus assisting springs 26-25 to apply the brakes. At the same time Iair inlet pipe 30 is open to the atmosphere, releasing the air pressure opposing springs 26--26- The brakes will be operated by rthe air pressure between diaphragm 4 and cover 22 even though springs 26-26 break, and, as has been mentioned, the brakes will be operated by springs `21S-26 even though diaphragm 4 ruptures or the air pressure fails.

Nut 2S normally is not screwed on s-tud 27. If it is necessary to release the ybrakes Without the use of air pressure nut 28 is screwed on thread 31 of stud 27 against bottom face 24 of bottom housing 22. This causes push plate 2S to be drawn to the lef-t in FIGURE 4, together with all elements of my apparatus attached thereto.

I'claim:

l. A break-actuating duid-operated motor comprising a first housing closed at both ends, a `first diaphragm disposed across the first housing intermediate its ends, ya second housing closed at one end positioned with its closed end adjacent to an end of the first housing, fthe first and second housings being movable with -respect to each other, a second diaphragm disposed across the second housing intermediate its ends, a rst push plate disposed against the first diaphragm, a push rod attached at one end to the lfirst push plate and extending :through the adjacent ends of the `first and second housings, a second push plate attached to the push rod at its other end and positioned between the closed end of the second housing and the second diaphragm, a third push plate disposed lagainst the other side of the second diaphragm, a brake operating rod attached to the third push plate, means for introducing fluid under pressure into the second housing only so as to -ex the second diaphragm and thereby move the brake operating rod, and means for introducing fluid under pressure into the rst housing only so as to flex the iirst diaphragm and thereby move the push rod.

2. Apparatus of claim l including a fourth push plate disposed against the first diaphragm on .the other side from the rst push plate and compressible spring means disposed between the r'ourth push plate and the end of the tirs-t housing.

3. Apparatus of claim 2 in which the central portion of the end of the iirst housing projects inwardly to form a depression in the iirst housing, and the fourth push plate is provided with a stud projecting through the depression .and having a threaded outer end `and a mating nut longer than the depression.

4. Apparatus of claim l in which the second housing is provided W-ith stop means positioned to limit the movement imparted to the brake operating rod by the second diaphragm to an `amount lessl than that imparted to the push rod by the iirst diaphragm.

5. Apparatus of :claim l including a thrid housing attached to the tirst housing and enclosing the second housing, and compressible spring means disposed between the third push plate and the end of the third housing.

6. Aparatus `of claim 2 in which the means lfor introducing fluid under pressure into the first housing includes a port opening into the tirst housing on the dirst push plate side of the first diaphragm.

7. A brake-actuating duid-operated motor comprising a first housing closed at both ends, a rst diaphragm disposed across the iirst housing intermediate its ends, a -second housing closed at one end positioned with its closed end `adjacent to an end of the irst housing, the first and second housings being moveable with respect to each other, a second diaphragm disposed lacross fthe second housing intermediate its ends, a Iiirst push plate disposed against lthe irst diaphragm, `a push `rod attached .at one end .to the iirst push plate and :extending through the adjacent ends of the drst and second housings, la second push plate attached to ythe push lrod -at its other end and positioned between the closed end of the second housing and the second diaphragm, a third push plate disposed against the other side of the second diaphragm, a brake operating rod lattached to the third push plate, a fourth push plate disposed against the first diaphragm on the other side from the Ir-st push plate, compressihle spring means disposed hetween the fourth push plate and the end of the iirst housing, rst means for introducing fluid under pressure into the second housing between its closed end land the second diaphragm, second means for introducing fluid under pressure into the rst housing fon fthe iirst push plate side of the ti-rst diaphragm, yand third means for introducing iiuid under pressure into the iirst housing on the founth .push plate side of vthe yfirst diaphragm.

8. Apparatus of claim 7 in `which fthe second and third means for introducing iiuid under pressure `are supplied from a common source of iiuid under pressure and are connected thereto .through a four-way Valve.

References Cited in the ile of this patent UNITED STATES PATENTS 2,754,805 Bernau July 17, 1956 2,962,000 Altieri Nov. 29, 1960 FOREGN PATENTS 522,107 Germany Apr. 4, 1931 

1. A BREAK-ACTUATING FLUID-OPERATED MOTOR COMPRISING A FIRST HOUSING CLOSED AT BOTH ENDS, A FIRST DIAPHRAGM DISPOSED ACROSS THE FIRST HOUSING INTERMEDIATE ITS ENDS, A SECOND HOUSING CLOSED AT ONE END POSITIONED WITH ITS CLOSED END ADJACENT TO AN END OF THE FIRST HOUSING, THE FIRST AND SECOND HOUSINGS BEING MOVABLE WITH RESPECT TO EACH OTHER, A SECOND DIAPHRAGM DISPOSED ACROSS THE SECOND HOUSING INTERMEDIATE ITS ENDS, A FIRST PUSH PLATE DISPOSED AGAINST THE FIRST DIAPHRAGM, A PUSH ROD ATTACHED AT ONE END TO THE FIRST PUSH PLATE AND EXTENDING THROUGH THE ADJACENT ENDS OF THE FIRST AND SECOND HOUSINGS, A SECOND PUSH PLATE ATTACHED TO THE PUSH ROD AT ITS OTHER END AND POSITIONED BETWEEN THE CLOSED END OF THE SECOND HOUSING AND THE SECOND DIAPHRAGM, A THIRD PUSH PLATE DISPOSED AGAINST THE OTHER SIDE OF THE SECOND DIAPHRAGM, A BRAKE OPERATING ROD ATTACHED TO THE THIRD PLATE, MEANS FOR INTRODUCING FLUID ENDER PRESSURE INTO THE SECOND HOUSING ONLY SO AS TO FLEX THE SECOND DIAPHRAGM AND THEREBY MOVE THE BRAKE OPERATING ROD, AND MEANS FOR INTRODUCING FLUID UNDER PRESSURE INTO THE FIRST HOUSING ONLY SO AS TO FLEX THE FIRST DIAPHRAGM AND THEREBY MOVE THE PUSH ROD. 